What does Liebert DS unit alarm 'High Room Temp' indicate?

A 'High Room Temp' alarm on the Liebert DS indicates the return air temperature has exceeded the alarm setpoint (default 27°C, adjustable). Common causes: high IT load above CRAC capacity, blocked floor tiles reducing airflow to equipment, failed or undersized supplemental cooling, or a refrigerant shortage reducing cooling capacity. Check supply air temperature — if supply air is also warm, the refrigeration system needs investigation.

How do I clear alarms on a Liebert DS unit?

Active alarms on the Liebert DS clear automatically when the condition returns to normal. Latched alarms (persisting after the condition clears) are cleared by pressing the Alarm Reset button on the front panel. For the iCOM controller, navigate to Alarms > Clear Latched to reset all cleared conditions. Review alarm history before clearing to identify recurring faults.

How do I configure a Liebert DS unit for economizer mode?

The Liebert DS economizer (free cooling) mode is configured via the iCOM controller under Setpoints > Economizer. Set the outdoor air enthalpy or dry bulb temperature switchover point, deadband, and minimum runtime before switching. In economizer mode, the compressor is off and the unit uses outdoor air or fluid cooler heat rejection for cooling. Verify the outdoor air damper actuator operates correctly before enabling economizer.

HVAC

Liebert error codes, decoded.

Look up any Liebert fault code below. Each one is grounded in Liebert's own service documentation — the meaning, the symptoms, the causes, and the steps to clear it.

By Octavian Ghindea

Co-founder & CTO · Reviewed August 2026

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Liebert sits in our HVAC coverage. Every page here is transcribed from the manufacturer's manuals, not scraped from forums.

What error codes does Liebert display?

Tap a code for the full breakdown — meaning, symptoms, causes, and fix steps.

High Room Temp

Return air exceeds setpoint — check IT load and airflow

Low Suction Pressure

Refrigerant charge low or expansion valve fault

High Head Pressure

Condenser problem or ambient too high

Loss of Airflow

Fan motor fault or blocked filter

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